ww2 sling ?

[painter777]

Sling on the carbine is what Bruce M said, A Reproduction.

Never in any era was it used by GI's.

Real D tips slings came in to use Post WWII.

IIRC, the picture you added of the 3 slings, the one in the middle with the TRW snap, I believe was very late Vietnam... but I'd need to double check on TRW hardware.